1. Field of the Invention
The present invention relates to a page printer in which a light beam controlled in accordance with a data signal is radiated onto a photosensitive body so as to record characters and patterns on paper.
2. Description of the Related Art
In order to improve printing quality and printing speed, a page printer utilizing the principle of "xerography" has been developed in which a light beam is controlled in accordance with printing data so that a latent image is formed on a photosensitive drum, and colored toner is adhered to the latent image and then fixed on the paper being printed.
To facilitate maintenance and the like, such a page printer is typically made in a clamshell configuration. Thus, as shown in FIG. 10, the printer housing M is divided into two members N and Q so as to provide a large access opening. A light writing unit is housed in one half Q and a photosensitive drum, a developing unit, etc. are housed in the other half N. Further, a paper conveying path is provided from one side to the other side of the housing so that printing paper is fed from a paper cassette R provided on the one side of the housing. A substrate S of a controlling electronic circuit is housed in the housing N in its bottom portion so as not to hinder the formation of the light path.
With such a structure, when the circuit substrate has to be adjusted or otherwise maintained, it is necessary to invert the housing so as to expose the circuit substrate. Thus, it is impossible to operate the printer during adjustment of the circuit substrate.